I remember this thread from months ago - and it scares me still...
There are a couple reasons for the conflicting specs:
A race car is much more likely (and have much higher dynamic loads) to experience a rollover than a street car, so they emphasize keeping the driver down. Especially since double shoulder straps are better than a single diagonaly belt at restraining forward motion.
Without a crotch strap to keep you from submarining, you're better off with a higher top mounting.
Does that bring things into perspective?
